myObject = {a: 1, b: 2, c: 3}
clonedObjectA = Object.assign(myObject);
clonedObjectB = {myObject};
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
A new clone via Object.assing | |
A new clone via spread operator |
Test name | Executions per second |
---|---|
A new clone via Object.assing | 23075276.0 Ops/sec |
A new clone via spread operator | 4724317.5 Ops/sec |
Let's break down the provided JSON benchmark definition and explain what is being tested, compared options, pros/cons of each approach, library usage, special JavaScript features or syntax (if applicable), and other considerations.
Benchmark Definition:
The benchmark defines two test cases to measure the performance difference between using Object.assign()
and the spread operator ({...}
) to create a new copy of an object. The script preparation code creates a simple object myObject
with three properties (a
, b
, and c
) and assigns it to a variable.
Individual Test Cases: There are two test cases:
Object.assign()
method to create a shallow copy of myObject
. The benchmark definition is clonedObjectA = Object.assign(myObject);
.{...}
) to create a new object that inherits properties from myObject
. The benchmark definition is clonedObjectB = {...myObject};
.Options Compared: The two options being compared are:
Object.assign()
method: Creates a shallow copy of an object, copying all enumerable own properties to a new object.{...}
): Creates a new object that inherits properties from the original object.Pros and Cons of Each Approach:
Object.assign()
:{...}
):Library Usage: None of the test cases use any external libraries.
Special JavaScript Features or Syntax (if applicable): Neither test case uses any special features or syntax, as both options are standard methods in modern JavaScript. The spread operator was introduced in ECMAScript 2015 and is widely supported across browsers.
Other Considerations:
myObject
) to minimize the overhead of object creation and property assignment.Alternatives: Other methods for creating a new copy of an object include:
Object.create()
with Object.assign()
: Creates a new object using Object.create()
and then assigns properties to it using Object.assign()
.JSON.parse(JSON.stringify())
: A widely supported method, but not as efficient as the spread operator.cloneDeep()
function (for deeper cloning of objects).These alternatives may have their own trade-offs in terms of performance, memory usage, and browser support.